华南石炭纪岩关-大塘界线期牙形石地层分带   总被引：4，自引：0，他引：4  

田树刚  M.科恩 《地质通报》2004,23(8):737-749

系统采集不同沉积相区和连续沉积的剖面，即浅海台地相广西柳江龙殿山剖面、台缘缓坡相云南施甸鱼硐剖面和台内盆地相广西柳州碰冲剖面，运用数理统计方法，研究了华南岩关一大塘界线过渡期牙形石的产出丰度和相分布，在恢复生物演化序列的基础上，对各剖面首先详细分带，再进一步综合成系统的5个牙形石带，即Gnathodus typicus—G．cuneiformis带、Gnathodus typicus—Protognathodus cordiformis带、Scaliognathus anchoralis—Gnathodus pseu-dosemiglaber带、Gnathodus praebilineatus带和Paragnathodus horrtopunctatus带。以生物系统发生为标准，严格限定各带的界线，并与北美、西欧同期地层进行精确对比，为建立杜内阶一维宪阶界线的全球层型(GSSP)提供可靠依据。  相似文献   

水位下降卸荷诱发库岸边坡快速失稳机理分析   总被引：6，自引：0，他引：6  

包太  刘新荣  税月 《水文地质工程地质》2004,31(5):7-11

本文以某工程现场岩质边坡为例，采用与传统裂隙水压力分布不同的水压力分布方式和边坡裂隙中可能发生的水锤效应相耦合，分析研究了岩质边坡发生滑动的机理及稳定性。研究表明，本文所采用的水压力分布方式较为符合边坡中的水压力分布实际情况，可以给出一个较为合理的稳定系数。当考虑水锤效应时，岩质边坡的稳定系数大大降低，说明水锤效应加剧了边坡破坏失稳的过程。本文所采用的水压力分布方式与边坡裂隙中的水锤效应相耦合的计算方法，在边坡稳定性分析中具有参考意义。  相似文献   

A probabilistic approach for computing water retention of particulate systems from statistics of grain size and tessellated pore network     

Richard Wan  Mehdi Pouragha  Mahdad Eghbalian  Jérôme Duriez  Tai Wong 《国际地质力学数值与分析法杂志》2019,43(5):956-973

The paper offers an analytical determination of the hydraulic properties of an unsaturated soil with reference to its retention curve, which describes the relationship between the volumetric water content and capillarity through matric suction. The analysis combines a particulate approach focused on the physics at the pore scale, including microstructural aspects, with a probabilistic approach where the void space and grain size are considered as random variables. In the end, the soil water characteristic curve of an unsaturated granular medium along a drying path can be derived analytically based on the sole information of particle size distribution. The analysis hinges on the tessellation of a wet granular system into an assemblage of tetrahedral unit cells revealing a pore network upon which capillary physics are computed with respect to pore throat invasion by a non-wetting fluid with evolving pendular capillary bridges. The crux of the paper is to pass from particle size probability distribution to a matching void space distribution to eventually reveal key information such as void cell and solid volume statistics. Making reasonable statistically based assumptions to render calculations tractable, the water retention curve can be readily constructed. Model predictions compare quite favourably with experimental data available for actual soils, especially in the high saturation range. Having a sound scientific basis, the model can be made amenable to address a variety of soils with a wider range of particle sizes.  相似文献   

Research on mining-induced deformation and stress,insights from physical modeling and theoretical analysis     

Guodong Li  Shugang Cao  Feng Luo  Yong Li  Yaxing Wei 《Arabian Journal of Geosciences》2018,11(5):100

The dynamic change of mining-induced stress is the main reason for large deformation of surrounding rock. To investigate the influence of mining-induced stress and deformation is important for appropriate supportive design. It also helps to raise the safety and productivity of longwall mining operations. In this paper, Weijiagou Coal Mine in Southwest China was selected as the case study. In order to research on the deformation and breakage of overlying strata, physical modeling test was carried out on the self-developed rotatable physical similar test system. By using digital image correlation (DIC) technique, the deformation of strata and development of cracks in the process of coal seam excavation were acquired, meanwhile, mining-induced stress was also monitored by pressure cell and strainmeter. According to the mechanical structure of stope, the height of the destressed zone has a significant influence on stress distribution. In order to minimize the discrepancy between the physical model test and theoretical analysis, the dimension of the plastic zone of roadway was added into the mining panel width, and the gap between the experimental and theoretical results reduced.  相似文献   

用超速CT机检测99例无症状香港中国人降低钙指数     

吴敬文  戴有鼎 《CT理论与应用研究》1994,3(4):34-34

回顾分析Ｍａｔｉｌｄａ医院超速ＣＴ室筛选首批病人中９９例中国人资料，很明显从通常采用１３０－１００Ｈｏｕｎｓｆｉｅｌｄ单位作为检出冠状血管钙化的基数应用至中国人身上其阈值数目需要降低，同时，我们也发现如果病人年龄按每１０年范围分组（２１－３０，３０－４０，４１－５０，５１－６０）而计算其超速ＣＴ的钙化指数会较随机男女一起按平均计算更易区分其差异．进一步分析显示，男性中年时候超速ＣＴ指数已达最高值，而女性则晚１０年方达最高值，因此，为了更易探测冠脉循环内钙化倾向应作出超速ＣＴ检出钙化的指数数目．这些实践经验对动脉粥样硬化过程的预测或预防有实际意义．  相似文献   

将C/S移植到CICS三层次结构的方法技术研究   总被引：2，自引：0，他引：2  

赵太银  李正文 《物探化探计算技术》2002,24(3):279-283

由于其低成本和易于编程，两层次的C／S结构是目前流行的体系结构。但因为两层次C／S结构固有的局限性，当系统大到一定程度时，我们必须要采用多层次的体系结构，而IBM公司的CICS是开发大型分布式应用系统的主流代表之一。作者在本文中介绍了将PowerBuider开发的两层次C／S结构移植到CICS三层次结构的简单方法。  相似文献   

DT—1016型阴离子交换树脂分离富集金铂钯   总被引：17，自引：5，他引：17  

甘树才  段太成等 《岩矿测试》2002,21(2):113-116

研究了DT－1016型阴离子交换树脂对超痕量Au,Pt,Pd的吸附性能及条件。在0.025mol/L HCl介质中，流出速度为0.5-1.0mL/min时，Au,Pt和Pd的富集效果最佳，吸附率分别为99.72％，99.06％和97.95％，共存离子无显著性影响。用等离子体质谱测定标准物质中Au，Pt和Pd，其结果与标准值基本相符。检出限Au为0.27μg/L，Pt为0.40μg/L，Pd为0.19μg／L。对GBW 07294铂族元素国家标准物质进行精密度试验，RSD（n=8）Au为19．2％，Pt为28.1％，Pd为15.6％。  相似文献   

江西安远路迳金伯利质煌斑岩筒的Rb-Sr同位素年龄及其地质意义   总被引：1，自引：2，他引：1  

叶松  杨眉  叶德隆  邰道乾  任迎新 《地质科技情报》2001,20(2):27-29

报道了赣南安远县路迳金伯利质煌斑岩筒的 Rb-Sr等时线地质年龄 :t=( 3 7.6± 2 .2 ) Ma,初始值 [n( 87Sr) / n( 86Sr) ] i=0 .70 5 17± 0 .0 0 0 12。  相似文献   

水--煤层气两相流体在煤层中的渗流规律   总被引：1，自引：1，他引：1  

张永利  邰英楼  王来贵 《地质灾害与环境保护》2001,12(4):63-66

采用煤体承受有效应力、水-气混合流动及固一流相互作用的基本原理，建立了煤层气开采过程中水-煤层气两相流渗的基本方程，通过自行设计的实验装置，测定了煤层中水-煤层气共同流动时的两相流体的流量，渗透率及随水的饱和度变化关系，并据此模拟出了反映水-煤层气渗透基本规律，从而为煤层气开采提供了理论基础。  相似文献   

Early-Middle Permian Reef Frameworks and Reef-building Models in the Eastern Kunlun Mountains   总被引：3，自引：0，他引：3  

TIAN Shugang Institute of Geology  Chinese Academy of Geological Sciences  Beijing  FAN Jiasong Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing 《《地质学报》英文版》2001,75(2):115-125

Reef frameworks and building models of the Early-Middle Permian in the eastern Kunlun Mountains have been verified through studies of reef-building communities, palaeoecology and carbonate facies. The eastern Kunlun reefs are built mainly by 6 reef-building communities, which include 11 major categories of frame-building organisms and 6 categories of reef-associated organisms. Eight types of reef-frames have been distinguished and eleven kinds of rocks identified to belong to 6 reef facies. Three sorts of reefs classified by previous researchers, namely mudmounds, knoll reefs and walled reefs, are well developed in the study area. Such reef-facies association and reef distribution show that there are 4 models of reef growth and development, i.e. the tidal-bank knoll-reef model, the plateau-margin wall-reef model, the composite wall-reef model and the deep-water mudmound model. The reefs are mainly constructed by calcareous sponge and calcareous algae, which are similar to all Permian reefs in other area  相似文献